The World Wide Web has become a popular medium of communication. Information on a wide variety of topics is available with just a few clicks of a mouse. However, in many cases, there are significant costs associated with the production of the information content available on the Web. Content providers must be compensated for these costs in order to remain viable. Several compensation schemes have been devised. One such scheme is to provide the desired content without charge to the consumer, but to include paid advertisements with the desired content. The payments by advertisers for the advertisements constitutes the compensation received by the content provider.
Advertisers pay for the delivery of their message to consumers. Advertiser's willingness to pay depends upon the number of consumers who receive the advertising message. The greater the number of consumers reached, the more advertisers are willing to pay. In addition, advertisers are willing to pay extra to reach demographic groups that are more likely than average to be receptive to a particular advertising message. However, a problem arises on the World Wide Web because the architecture of the Web makes it difficult to obtain accurate measurements of the numbers and demographic attributes of consumers receiving a particular advertising message. While the number of times a particular advertising message has been delivered from a server may be precisely measured, it is not known how to correlate such delivery measurements with actual consumers reached. For example, an indeterminable portion of the total accesses to a server may be due to automated agent machines, such as "web crawlers", which are searching the Web for data collection, indexing and filtering. As another example, a single access to a server might be made by a "proxy server", which then saves the content and re-distributes it to a user community. The size of this user community cannot be determined by the original server. A further problem arises in that, even if the number of consumers reached by an advertisement were measurable, the demographic attributes of those consumers still could not be measured.